Every display product has a gamma value. In terms of white organic light emitting diode (WOLED) display panels, the gamma value of each display panel may vary as color coordinates or electroluminescent efficiency thereof varies. Moreover, as the usage time of the display panel increases, an electroluminescent device is aged, and electroluminescent efficiency thereof decreases accordingly, thereby resulting in a change in the gamma value.
Currently, a large-size light emitting diode display panel generally has a structure in which a white light emitting diode cooperates with a color filter. White balancing is needed before adjusting the gamma value, and the gamma value for each of red (R), green (G), blue (B), and white (W) colors needs to be adjusted separately.
At present, gamma curve adjustment is achieved by actually measuring voltage values required when each of nine points with known gray-scales (specified by IC spec) reaches a desired brightness corresponding thereto. Therefore, for each display panel, it is necessary to measure gray-scale voltage values of 36 (=(RGBW)4*9) points in total. In addition, in order to cope with changes in data voltage, multiple groups of gamma values may need to be set before a light emitting diode display panel leaves the factory, for example. Gamma2 (i.e., gamma value of 2), Gamma2.2 (i.e., gamma value of 2.2). Gamma2.4 (i.e., gamma value of 2.4) and the like are set for each of brightness of 100 nit and brightness of 150 nit. For each group of gamma values, 36 points need to be measured, and thus it takes a lot of time to test multiple groups of gamma values, which makes it difficult to meet the deadlines of mass production.